This invention relates to vascular access systems implanted in individuals for the infusion of medication and the like, and particularly to vascular access systems which permit repeated introduction of medication into the device with minimal tissue damage to the individual.
In the treatment of many illnesses, it is necessary to repeatedly infuse medication directly into the bloodstream, into a particular organ, or otherwise to a particular medication site. For example, various chemotherapy regimes for treatment of cancerous conditions require frequent periodic medication. Bowel diseases and bone infections are other examples of conditions which require repeated treatment, as does the periodic dispensing of pain medication for terminally ill patients. In such frequent medication situations, to avoid having to locate a blood vessel for injection by a needle each time, various implantable devices have been developed to administer medications, including, for example external extending catheters, such as those referred to as BROVIAC, GROSHONG, and HICKMAN catheters. While there are differences between these external extending catheters, in the medical trade these various catheters are generally collectively referred to as BROVIAC-type catheters, or xe2x80x9cBROVIACS.xe2x80x9d Often, the medication is toxic in concentrated amounts and, therefore, must be infused through the catheter into a large volume of blood, such as through a large vein or a chamber in the heart. To accomplish this, one end of the catheter is fed through a vessel to a large vein or a chamber of the heart while the other end of the catheter projects through the patient""s skin to permit medication to be injected into the catheter. Typically, the externally extending catheters are implanted using a guide wire, which is inserted into the body and directed to the point of application through the cannula of a large needle. Once the guide wire is in place in the body, a sheath is fitted on a dilator and guided down the guide wire by the dilator. When the dilator is withdrawn, the sheath forms a tunnel through the body to the point of application. The distal end of the catheter is then directed to the point of application through the sheath, leaving the proximate end of the catheter extending from the body. The sheath is formed from peel away sections, which are separated to remove the sheath and leave the catheter extending into the body to the selected treatment site.
Another prior art technique of installing a catheter is referred to as a direct cutdown technique, in which an incision is made over the vein and the catheter is then inserted directly into the vein without use of a guide wire. The tunnel may be formed using a second cutdown or skin incision and a sharp tipped hollow metal trocar tunneling device.
An advantage of the externally extending catheters is that they can be inserted under light anesthesia on an outpatient basis. Furthermore, they tend to require non-invasive procedures, requiring only a small incision in the skin. Moreover, the procedure is relatively quick. An external extending catheter can be implanted or removed in a matter of fifteen minutes or thereabouts. Moreover, the externally extending catheter can be used for numerous applications, such as chemotherapy, treatment of bowel disease, blood product infusions, bone infection, and can be used to administer pain medicines for terminally ill or seriously injured persons.
A problem that arises with some implanted vascular access systems is that, despite steps taken after they are used to keep them clean, the catheter may become infected. Given sufficient time, any catheter system which leaves the access opening external of the body will necessarily develop infection at the site where the catheter passes through the skin. However, as described, disadvantages of the externally extending catheter include a significant likelihood of infection at the point of exit from the body. In addition, the protruding catheters have the added disadvantage of creating an unsightly and somewhat intimidating medical device that protrudes from the body, and, as a result, has the added disadvantage of placing a restriction on the patient""s activities. The patient cannot swim or engage in numerous other activities that would expose the catheter exit site to an even greater risk of infection.
Another general type of system which is implanted is generally referred to as a vascular port, such as, for example, PORT-A-CATH (copyright), available from Pharmacia Deltec, Inc., in St. Paul, Minn., or as disclosed in U.S. Pat. No. 5,281,205 to McPherson, or VITAL-PORT(copyright) available from Cook Inc. in Bloomington, Ind. More recently, ports have been used in conjunction with catheters to permit the catheter to be fully implanted. Vascular ports eliminate some of the disadvantages of the externally extending catheters. Since vascular ports are implanted beneath the skin, they eliminate some of the risk of infection. Furthermore, the patient is generally able to engage in most activities, including swimming. However, vascular access ports require a more invasive surgical procedure in order to implant or remove the port in or from the body. Conventional vascular ports require that a large incision be made in the skin and a cavity physically excavated below the skin to receive the port device. Moreover, the port is typically sutured to the muscle fascia. Once the port is in place and the delivery tubing is inserted and directed to the site of application, the incision is closed, leaving a relatively large scar site and protrusion of the skin at the port location. The medication is then delivered to the port transdermally by a needle, which is pushed through the skin and into the chamber of the port through a membrane, such as a silicone membrane. The disadvantage of the port is that it requires an invasive and more time consuming surgical procedure. Therefore, the procedure is, in general, significantly more expensive than the procedure for implanting for conventional externally extending catheters. Furthermore, when the port gets infected, the infection tends to be a large infection and requires similarly invasive procedures for removal of the vascular port.
One difficulty when using conventional ports is that they are hard to connect to the catheter since they often require small clamps to be manipulated in order to seal the catheter onto the port. The use of surgical gloves makes the manipulation of these clamps even more difficult.
In addition, heretofore, ports that are fabricated from all plastic components, though less expensive and easier to fabricate than metal ports or hybrid ports, such as disclosed in U.S. Pat. No. 5,387,192 to Glantz, often do not exhibit effective seals with the membrane. This may result form variations in tolerances of the port parts or from the material characteristics of plastic or a combination of both.
Consequently, there is a need for a vascular access device which can be inserted into the body of a patient with less trauma to the patient, easier to use, and, further, which is easier to manufacture and, therefore, less costly.
Accordingly, the present invention provides a new and unique vascular access device, which provides a venous and arterial implantable access device designed to permit repeated access to the vascular system for the parenteral delivery of medications, nutritional solutions, and other fluids to selected sites within the vascular system and for sampling of venous blood.
According to one aspect of the invention, a vascular access device includes an implant body having at least one access chamber for receiving medical treatment and a first opening in communication with the access chamber. The implant body has first and second ends and a cannula in communication with the access chamber. The first end is formed by a clamp and is pointed an amount sufficient to separate tissue and, thereby, ease insertion of the implant body through an insertion location, such as an incision, to a placement location remote from the insertion location without excavation of the placement location. A tubular member having at least one lumen extending therethrough is clamped onto the cannula by the clamp to provide communication with the access chamber through the cannula for delivering medical treatment from the access chamber to a preselected treatment site in the body of the patient remote from the placement location. A membrane covers and seals the first opening and is adapted to receive a percutaneous needle puncture without leakage from the puncture.
In one aspect, the second end of the implant body is generally pointed an amount sufficient to separate tissue in order to ease removal of the vascular access device.
In another aspect, the clamp includes a transverse passage formed therein, with the cannula and tubular member positioned in the transverse passage. Preferably, the clamp includes a pair of clamp halves. In one aspect, each of the clamp halves includes a plurality of grooves, which are located in the transverse passage and which induce regions of decreased compression and regions of increased compression between the grooves on the tubular member. The tubular member at least partially extends into the grooves when the clamp halves clamp the tubular member onto the cannula whereby the tubular member is substantially anchored on the cannula by the clamp halves. In other aspects, the clamp halves include a plurality of ribs formed in the transverse passage. The ribs form regions of increase compression at the ribs and regions of reduced compression between the ribs such that the tubular member at least partially extends into the regions between the ribs such that the tubular member is substantially anchored on the cannula by the clamp halves. In yet another aspect, the cannula includes at least one projection, with the projection generating at least one region of increased compression on the tubular member at the projection and regions of reduced compression adjacent the projection such that the tubular member at least partially extends into the regions of the reduced compression whereby the tubular member is substantially anchored on the cannula by the clamp halves.
According to another form of the invention, the vascular access device includes an elongated body having a first and a second end. The second end comprises a closed end, with the first end comprising a clamp. The elongated body is tapered from a medial portion of the elongated body to the first and second ends to form pointed first and second ends to ease insertion or removal of the vascular access device. The elongated body includes an access chamber formed therein for receiving the medical treatment and, further, includes an access opening in fluid communication with the access chamber. A cannula is provided which is in fluid communication with the access chamber. A catheter tube is clamped onto the cannula by the clamp and has a lumen which is in fluid communication with the access chamber of the elongated body through the cannula for delivering medical treatment from the access chamber to a preselected location on the body. A membrane seals the access chamber and is adapted to receive a percutaneous needle puncture without leakage from the puncture.
In one aspect, the clamp comprises a pair of clamp halves. The elongated body preferably includes a landing with the clamp halves being coupled to the landing. In further aspects, the landing extends around the cannula and the clamp halves form a transverse passage therebetween in which the tube is clamped onto the cannula. In other aspects, one of the cannula and the transverse passage includes either projections or recesses to thereby form regions of increased compression and decreased compression on the tube.
According to yet another form of the invention, a vascular access device includes a base portion, which has a chamber, and a top portion, which is mounted to the base portion and includes an access opening which is generally aligned with the chamber. A membrane seals the chamber and is adapted to receive a percutaneous puncture without leakage from the puncture and, further, is accessible through the access opening. A tube is mounted on a cannula, which is in communication with the chamber. A clamp clamps and seals the tube on the cannula. The base, the top portion, and the clamp form an elongated implant body having first and second ends, with the first end comprising the insertion end and being sufficiently pointed to separate tissue when inserted into the body and with the first end being defined by the clamp. In one aspect, the base and the top portion both include a landing, with at least one of the landings including an engagement surface for receiving and engaging a corresponding engagement structure of the clamp to thereby couple the clamp to the top portion and the base portion. In further aspects, the clamp preferably comprises a pair clamps and, more preferably, a pair of clamps which are secured together by welding.
In this manner, the vascular access device can be completely subcutaneously implanted in the body without the extensive surgical techniques associated with conventional ports and, instead, may be implanted with the same ease as a catheter, while providing all the advantages of conventional ports. These and other advantages, benefits, and objects will be understood by one skilled in the art from the drawings, description, and claims which follow.